Organo-Lewis acid as cocatalyst for cationic homogenous metallocene Ziegler-Natta olefin polymerizations

ABSTRACT

The synthesis of the organo-Lewis acid perfluorobiphenylborane (PBB) and the activation of metallocenes for the formation of a variety of highly active homogeneous Ziegler-Natta metallocene olefin polymerization, copolymerization and ring-opening polymerization catalysts is described.

This invention was made with Government support under Contract No.DE-FG02-86ER13511 awarded by the Department of Energy. The Governmenthas certain rights in this invention.

This is a divisional of prior application Ser. No. 08/800,548 filed onFeb. 18, 1997, now U.S. Pat. No. 5,856,256.

BACKGROUND OF THE INVENTION

This invention relates to the compositions of matter useful ascatalysts, to a method for preparing these catalysts and to a method forpolymerization utilizing the catalysts.

The use of soluble Ziegler-Natta type catalysts in the polymerization ofolefins is well known in the prior art. In general, such systems includea Group IV-B metal compound and a metal or metalloid alkyl cocatalyst,such as aluminum alkyl cocatalyst. More broadly, it may be said toinclude a mixture of a Group I-III metal alkyl and a transition metalcomplex from Group IVB-VB metals, particularly titanium, zirconium, orhafnium with aluminum alkyl cocatalysts.

First generation cocatalyst systems for homogeneous metalloceneZiegler-Natta olefin polymerization, alkylaluminum chlorides (AlR₂ Cl),exhibit low ethylene polymerization activity levels and no propylenepolymerization activity. Second generation cocatalyst systems, utilizingmethyl aluminoxane (MAO), raise activities by several orders ofmagnitude. In practice however, a large stoichiometric excess of MAOover catalyst ranging from several hundred to ten thousand must beemployed to have good activities and stereoselectivities. Moreover, ithas not been possible to isolate characterizable metallocene activespecies using MAO. The third generation of cocatalyst, B(C₆ F₅)₃, provesto be far more efficient while utilizing a 1:1 catalyst-cocatalystratio. Although active catalyst species generated with B(C₆ F₅)₃ areisolable and characterizable, the anion MeB(C₆ F₅)₃ ⁻ formed after Me⁻abstraction from metallocene dimethyl complexes is weakly coordinated tothe electron-deficient metal center, thus resulting in a drop of certaincatalytic activities. The recently developed B(C₆ F₅)₄ ⁻ type ofnon-coordinating anion exhibits some of the highest reported catalyticactivities, but such catalysts have proven difficult to obtain in thepure state due to poor thermal stability and poor crystallizability,which is crucial for long-lived catalysts and for understanding the roleof true catalytic species in the catalysis for the future catalystdesign. Synthetically, it also takes two more steps to prepare such ananion than for the neutral organo-Lewis acid.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the subject invention to prepare andutilize a new class of olefin polymerization catalysts.

A further object of the subject invention is a catalyst which permitsbetter control over molecular weight, molecular distribution,stereoselectivity, and comonomer incorporation.

Another object of the subject invention a Ziegler-Natta type catalystsystem which reduces the use of excess cocatalyst and activatespreviously unresponsive metallocenes.

These and other objects are attained by the subject invention whereby inone embodiment, a strong organo-Lewis acid, such asperfluorobiphenylborane (PBB) is utilized as a highly efficientcocatalyst for metallocene-mediated olefin polymerization and as acatalyst for a ring opening polymerization of THF. PBB can besynthesized in much higher yield than B(C₆ F₅)₃ and the anion generatedwith PBB is non-coordinating instead of weakly coordinating as in thecase of B(C₆ F₅)₃. Thus, the former exhibits higher catalytic activitiesand can activate previously unresponsive metallocenes. The catalyticallyactive species generated with PBB are isolable, X-raycrystallographically characterizable instead of the unstable, oilyresidues often resulting in the case of B(C₆ F₅)₄ ⁻. In addition, PBBexhibits even higher catalytic activities in most cases.

In one embodiment of the subject invention a strong organo-Lewis acid,such as perfluorobiphenylborane (PBB), is utilized to synthesizestoichiometrically precise, isolable/crystallographicallycharacterizable, highly active "cation-like" metallocene polymerizationcatalysts. The biphenyl groups of PBB may be connected to the Boron atthe meta, para, or ortho position.

PBB reacts with early transition metal or actinide alkyls to yieldhighly reactive cationic complexes: (LL'MR)⁺ (RBR'R"⁻ ₂)⁻.

where L,L'=C₅ H_(n) R_(5-n), indenyl, allyl, benzyl, C₅ H_(n) R_(4-n)XNR

M=early transition metal or actinide, e.g., Ti, Zr, Hf, Th, U;

X=R₂ '"Si,R'" bridging alkyl or aryl group (C≦10)

R, R'"=alkyl, benzyl, or aryl group (C≦20), hydride, silyl;

B=Boron

R'=fluorinated biphenyl

R"=fluorinated phenyl, fluorinated biphenyl, or fluorinated polycyclicfused rings such as naphthyl, anthryl, or fluorenyl

As a specific example of the above, the reaction of PBB with a varietyof zirconocene dimethyl complexes proceeds rapidly and quantitatively toyield, after recrystallization from hydrocarbon solvents, the catalyticcomplex of Eq. 1. ##STR1## Such catalytic complexes have been found tobe active homogeneous catalysts for α-olefin polymerization and, moreparticularly, the polymerization, copolymerization oroligopolymerization of ethylene, α-olefins, dienes and acetylenicmonomers, as well as intramolecular C--H activation.

The cocatalyst of the subject invention may be referred to as BR'R",where B=Boron; R' and R" represent at least one and maybe morefluorinated biphenyls or other polycylic groups, such as naphthyl. Twoof the biphenyls may be substituted with a phenyl group. Both thebiphenyls and the phenyl groups should be highly fluorinated, preferablywith only one or two hydrogens on a group, and most preferably, as inPBB with no hydrogens and all fluorines.

The cocatalyst system of the subject invention can be better understoodwith reference to the drawings wherein:

FIG. 1 is a structural depiction of PBB;

FIG. 2 is a reaction pathway for the synthesis of PBB;

FIG. 3 shows the reaction pathway for a catalyst system according to thesubject invention;

FIG. 4 shows the reaction pathway for a second catalyst system accordingto the subject invention;

FIG. 5 shows the reaction pathway for a third catalyst system accordingto the subject invention; and

FIG. 6 shows the reaction pathway for a fourth catalyst system accordingto the subject invention.

DETAILED DESCRIPTION OF THE INVENTION

The reaction of perfluorobiphenylborane with a variety of ziconocene andother actinide or transition metal dimethyl complexes proceeds rapidlyand quantitatively at room temperature in noncoordinating solvents toyield, after recrystallization, complexes. This catalytic reaction maybe used in the polymerization, copolymerization, oligomerization anddimerization of α-olefins at temperatures of -78° C. to 200° C. Inaddition, the catalyst of the subject invention may be used as acocatalyst in conjunction with aluminum alkyls, aluminum aryls, (AlR₃,R=Et, Me, Ph, naphthyl) or methyl alumoxane (Al(CH₃)O)_(n) for increasedpolymer yields.

PBB (FIG. 1) has been synthesized in quantitative yields of 91% ascompared to the 30-50% yields experienced with B(C₆ F₅)₃, currently avery important Lewis acidic cocatalyst in industry (FIG. 2). The Lewisacidity of PBB has been shown to be much greater than that of B(C₆ F₅)₃by comparative reactions of Cp'₂ ThMe₂ with B(C₆ F₅)₃ and PBB (Cp'=C₅Me₅). The former reagent does not effect Me⁻ abstraction, while thelatter gives the catalyst shown in FIG. 3. The reaction of PBB with abis-Cp type of dimethyl zirconocenes forms a dinuclear methyl-bridgedzirconocene cation such as ##STR2## and a hydride-bridged analog such as##STR3## More particularly, reaction of PBB with group 4 and Th methylsproceeds cleanly to yield cationic complexes such as set forth below.##STR4##

For ethylene polymerization, catalytic activities of dinuclear cationsgenerated from PBB are greater than those of monomeric cations generatedfrom B(C₆ F₅)₃ presumably because (MePBB)⁻ is a non-coordinating anionas compared to the weakly coordinating anion MeB(C₆ F₅)₃. The dinuclearcations have also been found to catalyze the rapid ring-openingpolymerization of THF to produce poly(tetrahydrofuran), an importantthermoplastic elastomer and artificial leather. Monomeric zirconocenecations have also been generated in situ by the reaction of L₂ ZrMe₂ andPBB at 60° C. ##STR5## These attempts show very high activities forolefm polymerization, and identify (MePBB)⁻ to be a trulynon-coordinating anion. The polymerization data with metallocene cationshaving various anions are summarized in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Polymerization Data                                                           entry      μmol         polymer   M.sub.wd.sup.c                           no.                                                                              catalyst                                                                              of cat                                                                           conditions                                                                           monomer(s).sup.a                                                                    yield (g)                                                                          activity.sup.b                                                                     (10.sup.-3)                                                                       M.sub.w /M.sub.n                     __________________________________________________________________________                                             remarks                              1. (Cp.sub.2 ZrMe).sub.2 Me.sup.+                                                        15 100 mL toluene                                                                       ethylene                                                                            .80  4.80 × 10.sup.6                                                              559 3.06                                    MePBB.sup.-                                                                              25° C., 40 s                                             2. Cp.sub.2 ZrMe.sup.+                                                                   15 100 mL toluene                                                                       ethylene                                                                            1.00 4.00 × 10.sup.6                                                              124 2.03                                    MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 60 s                                             3. (Cp".sub.2 ZrMe).sub.2 Me.sup.+                                                       15 100 mL toluene                                                                       ethylene                                                                            1.30 7.80 × 10.sup.6                                                              392 2.72                                    MePBB.sup.-                                                                              25° C., 40 s                                             4. Cp".sub.2 ZrMe.sup.+                                                                  15 100 mL toluene                                                                       ethylene                                                                            1.50 6.00 × 10.sup.6                                                              321 1.42                                    MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 60 s                                             5. (Cp'.sub.2 ZrMe).sub.2 Me.sup.+                                                       15 100 mL toluene                                                                       ethylene                                                                            1.07 4.30 × 10.sup.6                                                              370 2.28                                    MePBB.sup.-                                                                              25° C., 60 s                                             6. Cp'.sub.2 ZrMe.sup.+                                                                  15 100 mL toluene                                                                       ethylene                                                                            0.80 3.20 × 10.sup.6                                                              136 2.54                                    MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C. 6O s                                              7. Cp'TiMe.sup.+.sub.2                                                                   50 5 mL toluene                                                                         styrene                                                                             0.35 1.61 × 10.sup.6                                                              170 2.56   [rrrr] > 98%                     MePBB.sup.-                                                                              25° C., 15 min                                           8. Cp'ZrMe.sup.+.sub.2                                                                   50 5 mL toluene                                                                         styrene                                                                             1.45 1.00 × 10.sup.7                                                              27.6                                                                              2.63   atactic                          MePBB.sup.-                                                                              25° C., 10 min                                           9. Cp'HfMe.sup.+.sub.2                                                                   50 5 mL toluene                                                                         styrene                                                                             0.69 3.17 × 10.sup.6                                                              24.8                                                                              2.98   atactic                          MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 15 min                                           10.                                                                              Cp'HfMe.sup.+.sub.2                                                                   50 5 mL toluene                                                                         styrene                                                                             1.16 5.33 × 10.sup.6                                                              22.9                                                                              2.78   atactic                          MePBB.sup.-                                                                              25° C., 15 min                                              Cp'TiMe.sup.+.sub.2                                                                   50 25 mL toluene                                                                        ethylene                                                                            0.70 1.70 × 10.sup.5                                                              848 23.7   39.5% hexane                     MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 5 min                                                                 1-hexene                   incorporation                    Cp'TiMe.sup.+.sub.2                                                                   50 25 mL toluene                                                                        ethylene                                                                            4.51 1.08 × 10.sup.6                                                              151 4.32   43.6% hexene                     MePBB.sup.-                                                                              25° C., 5 min                                                                 1-hexene                   incorporation                    CGCZrMe.sup.+                                                                         15 100 mL toluene                                                                       ethylene                                                                            0    --   --  --                                      MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 20 min                                              CGCZrMe.sup.+                                                                         15 100 mL toluene                                                                       ethylene                                                                            1.56 1.56 × 10.sup.6                                                              7.69                                                                              2.78                                    MePBB.sup.-                                                                              25° C., 4 min                                               CGCTiMe.sup.+                                                                         15 100 mL toluene                                                                       ethylene                                                                            0.21 8.40 × 10.sup.4                                                              1058                                                                              9.54                                    MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 10 min                                              CGCTiMe.sup.+                                                                         15 100 mL toluene                                                                       ethylene                                                                            0.83 4.98 × 10.sup.6                                                              305 2.56                                    MePBB.sup.-                                                                              25° C., 40 s                                                CGCZrMe.sup.+                                                                         50 25 mL toluene                                                                        ethylene                                                                            0    --   --  --                                      MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 15 min                                                                1-hexene                                                    CGCZrMe.sup.+                                                                         50 25 mL toluene                                                                        ethylene                                                                            6.97 5.58 × 10.sup.5                                                              10.0                                                                              2.68   33.6% hexene                     MePBB.sup.-                                                                              25° C. 15 min                                                                 1-hexene                   incorporation                    CGCTiMe.sup.+                                                                         25 25 mL toluene                                                                        ethylene                                                                            0.05 1.20 × 10.sup.4                                                                         63.2% hexene                     MeB(C.sub.6 F.sub.5).sub.3.sup.-                                                         25° C., 10 min                                                                1-hexene                   incorporation                 20.                                                                              CGCTiMe.sup.+                                                                         25 25 mL toluene                                                                        ethylene                                                                            1.95 4.68 × 10.sup.5                                                              105 1.86   65.3% hexene                     MePBB.sup.-                                                                              25° C., 10 min                                                                1-hexene                   incorporation                 __________________________________________________________________________     .sup.a 1 atm ethylene pressure; 17.4 mmol of styrene, and 44.5 mmol of        1hexene.                                                                      .sup.b g polymer/[(mol of cationic metallocene)atm h], except in entries      7-10: polystyrene/[mol catalyst) (mol monomer) h] (reproducibility betwee     runs ˜ 10˜15%).                                                   .sup.c GPC relative to polystyrene standards.                            

Other types of cationic metallocene catalyst systems can also be createdwith PBB. Metallocene cations of mono-Cp type (FIGS. 4 and 5) have beenformed by the reaction of mono-pentamethyl Cp trimethyl group IVcomplexes with and PBB. These are very good syndiospecific styrenepolymerization catalysts (FIGS. 4 and 5). Constrained geometry types ofzirconocene and titanocene cations such as those in FIG. 6 where m=Zr,Ti, are readily produced by the reaction of the corresponding dimethylmetallocenes with PBB. They are highly naked cations and much moreactive catalysts than those generated with B(C₆ F₅)₃.

EXAMPLES Example 1

Synthesis of Perfluorobiphenylborane (PBB)

n-Butyllithium (1.6 M in hexanes, 25 mL, 40 mmol) was added dropwise tobromopentafluorobenzene 18.0 g, 9.1 mL, 72.9 mmol) in 100 mL of diethylether over a cold-water bath. The mixture was then stirred for a further12 h at room temperature. Removal of solvent followed by vacuumsublimation at 60-65° C./10⁻⁴ torr gave 12.0 g of2-bromononafluorobiphenyl as a whiter crystalline solid: yield 83.3%.The dangerous and explosive nature of C₆ F₅ Li ether solutions in thispreparation can be avoided by (a) the use of excess of C₆ F₅ Br, (b)slow addition of n-butyllithium, (c) frequent change of the cold waterbath or use of a continuous flowing cold water bath.

To the above prepared 2-bromononafluorobiphenyl (5.0 g, 12.7 mmol) in amixed solvent of 70 mL of diethyl ether and 70 mL of pentane wasgradually added 8.0 mL of n-Butyllithium (1.6 M in hexanes, 12.8 mmol)at -78° C. The mixture was stirred for an additional 2 h, and borontrichloride (4.0 mL, 1.0 M in hexanes, 4.0 mmol) was then quickly addedby a syringe. The mixture was left at -78° C. for 1 h and thetemperature was then allowed to slowly rise to room temperature. Asuspension resulted after stirring an additional 12 h. It was filteredto give a yellow solution, and the solvent of the filtrate was removedin vacuo. The resulting pale yellow powder was sublimed at 140° C./10⁻⁴torr or 125° C./10⁻⁶ torr to produce a light yellow crystalline solid asan ether-free crude product. Recrystallization from pentane at -20° C.gave 3.5 g of the pure PBB as a white crystalline solid: yield 91.0%.Analytical and spectroscopic data for PBB are as follows. ¹⁹ F NMR (C₆D₆, 23° C.): δ -120.08 (s, br, 3 F, F-3), -132.09 (s, br, 3 F, F-6),-137.66 (s, br,6 F, F-2'/F-6'), -143.31 (t, ³ J_(F-F) =21.4 Hz, 3 F,F-4), ⁻ 149.19 (t, ³ J_(F-F) =21.7 Hz, 3 F.F-4'), -150.56 (t, ³ J_(F-F)=14.7 Hz, 3 F, F5), -160.72 (s, br, 6 F, F-3'/F-5'). ¹³ C NMR (C₆ D₆,23° C.): δ 150.92 (dd, ¹ J=_(C-F) =251.8 Hz, ² J_(C-F) =10.1 Hz, 3 C),146.35 (dd, ¹ J_(C-F) =254.3 Hz, ² J_(C-F) =12.1 Hz, 3 C), 144.26 (dd, ¹J_(C-F) =258.1 Hz, ² J_(C-F) =10.5 Hz, 6 C). 143.50 (tt, ¹ J_(C-F)=265.4 Hz, ² J_(C-F) =12.0 Hz, 3 C), 141.98 (tt, ¹ J_(C-F) =261.4 Hz,=11.7 Hz, 3 C), 141.17 (tt, ¹ J_(C-F) =254.3 Hz, ² J_(C-F) =10.5 Hz, 3C), 137.70 (tt. ¹ J_(C-F) =257.3 Hz. ² J_(C-F) =11.6 Hz, 6 C), 124.51(d, ² J_(C-F) =11.7 Hz, 3 C), 113.60 (d, ² J_(C-F) =11.5 Hz. 3 C),106.05 (s, br, 3 C). MS: parent ion at m/e 956. Anal. Calcd for C₃₆ BF₂₇: C, 45.22: H, 0.00. Found: C, 45.44; H, 0.05.

Example 2 Synthesis of Cp'₂ ThMe⁺ (MePBB)⁻

Cp'₂ ThMe₂ (0.106 g, 0.199 mmol) and PBB (0.191 g, 0.199 mmol) were inthe glove box charged into a 25-mL reaction flask with a filter plug,and the flask was attached to the high vacuum line. Benzene (15 mL) wasthen vacuum-transferred into this flask at -78° C. The mixture wasslowly allowed to warm to room temperature and stirred for 6 h. Thesolvent was removed, pentane (20 mL) was next vacuum-transferred intothe flask, and the mixture was filtered after stirring. The white solidwhich collected was dried under vacuum to give 0.210 g of product: yield70.9%. Analytical and spectroscopic data are as follows. ¹ H NMR (C₆ D₆,23° C.): δ 1.61 (s, 30 H, C₅ Me₅), 0.62 (s, 3 H, Th-CH₃), -095 (s, br, 3H, B--CH₃). ¹⁹ _(F) NMR (C₆ D₆, 23° C.): δ -124.57 (s, br, 3F), -138.10(s, br, 3 F), -139.28 (d, ³ J_(F-F) =21.4 Hz, 3 F), -139.74 (d, ³J_(F-F) =21.2 Hz, 3 F), -155.08 (t, ³ J_(F-F) 21.4 Hz, 3 F), -157.32 (t,³ J_(F-F) =22.0 Hz, 3 F), -162.20 (t, ³ J_(F-F) =22.0 Hz, 3 F), -163.13(t, ³ J_(F-F) =22.0 Hz, 3 F), -163.90 (t, ³ J_(F-F) =21.4 Hz, 3 F). ¹³ CNMR (C₆ D₆, 23° C.): δ 129.54 (C₅ Me₅), 79.28 (Th--Me), 10.44 (C₅ Me₅),10.25 (B--Me). Anal. Calcd for C₅₈ H₃₆ BF₂₇ Th: C, 46.79; H, 2.44; N,0.00. Found: C, 46.68; H, 2.24; N. 0.00.

Example 3 Synthesis of L₂ Zr(Me)(μ-Me)(Me)ZrL₂ ⁺ (MePBB)⁻ (L=C₅ H₅ (Cp),C₅ H₃ Me₂ (Cp"), or C₅ Me₅ (Cp')

L₂ ZrMe₂ (0.398 mmol) and PBB (0.199 mmol) were loaded into a 25mL-flask, which was then attached to the vacuum line. Pentane (20 mL)was then vacuum-transferred into this flask at -78° C. The mixture wasslowly warmed to room temperature and stirred for an additional 2 h(L=Cp), 15 h (L=Cp") or 48 h (L=Cp'). The resulting suspension wasfiltered, and the colored solids (light pink for Cp, light yellow forCp" and yellow for Cp') were washed with a small amount of pentane anddried under vacuum: yields 90.3% (Cp), 86.3% (Cp") and 34.7% (Cp').Analytical and spectroscopic data for L=C₅ H₅ are as follows. ¹ H NMR(C₆ D₆, 23° C.): δ 5.65 (s, 20 H, C₅ H₅), -0.04 (s, 6 H, Zr--CH₃), -0.84(s, br, 3 H, B--CH₃), -1.15 (s, 3 H, Zr--CH₃ --Zr). ¹⁹ F NMR (C₆ D₆, 23°C.): δ -124.20 (d, ³ J_(F-F) =16.6 Hz, 3 F), -138.98 (d, ³ J_(F-F) =20.3Hz, 3 F), -139.20 (d, ³ J_(F-F) =22.0 Hz, 3 F), -140.29 (d, ³ J_(F-F)=24.5 Hz, 3 F), -155.15 (t, ³ J_(F-F) =20.9 Hz, 3 F), -160.06 (t, ³J_(F-F) =22.3 Hz, 3 F), -162.79 (t, ³ J_(F-F) =22.0 Hz, 3 F), -163.11(t, ³ J_(F-F) =21.5 Hz, 3 F), -163.97 (t, ³ J_(F-F) =19.0 Hz, 3 F). ¹³ CNMR (C₆ D₆, 23° C.): δ 113.24 (C₅ H₅), 38.88 (Zr--CH₃), 21.53 (B--CH₃),15.80 (Zr--CH₃ --Zr). Anal. Calcd for C₆₀ H₃₂ BF₂₇ Zr₂ : C, 49.39; H,2.21; N, 0.00. Found: C, 48.97; H, 1.92; N, 0.00.

Analytical and spectroscopic data for L=C₅ H₃ Me₂ are as follows. ¹ HNMR (C₇ D₈, 23° C.): δ 5.51 (t, ³ J_(H-H) =2.8 Hz, 4 H, C₅ H₃ Me₂), 5.47(t, ³ J_(H-H) =3.2 Hz, 4 H, C₅ H₃ Me₂), 5.18 (t, ³ J_(H-H) =2.8 Hz, 4 H,C₅ H₃ Me₂).1.73 (s, 12 H, C₅ H₃ Me₂), 1.51 (S, 12 H, C₅ H₃ MMe₂), -0.26(s, 6 H, Zr--CH₃), -0.92 (s, br, 3 H, B--CH₃), -1.50 (s, 3 H, Zr--CH₃--Zr). ¹⁹ F NMR (C₆ D₆, 23° C.): δ 123.37 (d, ³ J_(F-F) =15.3 Hz, 3 F),-139.20 (d, ³ J_(F-F) =24.0 Hz, 3 F), -139.62 (d, ³ J_(F-F) =24.3 Hz, 3F), -139.89 (d, ³ J_(F-F) =24.0 Hz, 3 F), -155.81 (t, ³ J_(F-F) =21.4Hz, 3 F), -159.36 (t, ³ J_(F-F) =22.3 Hz, 3 F), -163.22 (t, ³ J_(F-F)=21.4 Hz, 3 F), -163.55 (t, ³ J_(F-F) =22.0 Hz, 3 F), -164.20 (t, ³J_(F-F) =22.6 Hz, 3 F). ¹³ C NMR (C₆ D₆, 23° C.): δ 114.20 (d, ¹ J_(CH)=171.7 Hz, C₅ H₃ Me₂), 113.62 (s, C₅ H₃ Me₂), 112.80 (s, C₅ H₃ Me₂),111.29 (d, ¹ J_(CH) =165.7 Hz, C₅ H₃ Me₂), 106,57 (d, ¹ J_(CH) =173.3Hz. C₅ H₃ Me₂), 41.63 (q, ¹ J_(C-H) =118.4 Hz, Zr--CH₃), 31.26 (q, ¹J_(CH) =116.5 Hz, B--CH₃), 22.21 (q, ¹ J_(CH) =134.3 Hz, Zr--CH₃ --Zr),12.94 (q, ¹ J_(CH) =128.0 Hz, C₅ H₂ Me₂), 12.71 (q, ¹ J_(CH) =127.6 Hz.C₅ H₂ Me₂). Anal. Calcd for C₆₈ H₄₈ BF₂₇ Z₂ : C, 51,98; H, 3.08; N,0.00. Found: C, 51.61; H, 3.00; N, 0.00.

Analytical and spectroscopic data for L=C₅ Me₅ are as follows. ¹ H NMR(C₆ D₆, 23° C.): δ 1.57 (s, 60 H, C₅ Me₅) -0.84 (s, br, 3 H, B--CH₃).The bridging and terminal methyl groups are discrete at low temperature.¹ H NMR (C₇ D₈, -13° C.): δ -0.19 (s, br, 6 H. Zr--CH₃), -0.92 (s, br, 3H, B--CH₃), -2.42 (s, br, 3 H, Zr--CH₃ --Zr). ¹⁹ F NMR (C₆ D₆, 23° C.):δ123.11 (d, s, br, 3 F), -139.27 (d, ³ J_(F-F) =20.3 Hz, 3 F), -139.67(t, ³ J_(F-F) =25.1 Hz, 6F), -155.73 (t, ³ J_(F-F) =20.9 Hz, 3 F),-160.91 (s, br, 3 F), -163.25 (t, ³ J_(F-F) =21.7 Hz, 3F), -163.56 (t, ³J_(F-F) =22.0 Hz, 3 F), -164.13 (t, ³ J_(F-F) =21.4 Hz, 3 F). Anal.Calcd for C₈₀ H₇₂ BF₂₇ Zr₂ : C, 55.23; H, 4.17; N, 0.00. Found: C,54.81; H, 3.98; N, 0.00.

Example 4 Synthesis of L₂ Zr(H)(μ-H)(H)ZrL₂ ⁺ (MePBB)⁻ L=C₅ H₅, C₅ H₃Me₂

The procedure here is similar to that of Example 3, except that thereaction was carried out under 1 atm of H₂ for 15 h: yields 81.6% (L=C₅H₅, grey solid) and 75.6% (L=C₅ H₃ Me₂, orange solid). Analytical andspectroscopic data for L=C₅ H₅ are as follows. ¹ H NMR (C₆ D₆, 58° C.):δ 6.67 (s, br, 2 H, --Zr--H), 5.64 (s, 20 H, C₅ H₅), -0.81 (s, br, 3 H,B--CH₃), -1.38 (s, br, 1 H, Zr--H--Zr). The chemical shifts andsplitting patterns of ¹⁹ F NMR are same as those of Example 3 (L=C₅ H₅).Anal. Calcd for C₅₇ H₂₆ BF₂₇ Zr₂ : C, 48.31; H, 1.85; N, 0.00. Found: C,47.90; H, 1.92; N, 0.00.

Analytical and spectroscopic data for L=C₅ H₃ Me₂ are as follows. ¹ HNMR (C₇ D₈, 23° C.): δ 5.81 (m, 4 H, C₅ H₃ Me₂), 5.50 (m, 4 H, C₅ H₃Me₂), 5,23 (m, 4 H, C₅ H₃ Me₂). 1.65 (m, 24 H, C₅ H₃ Me₂), 0.25 (s, br,2 H, Zr--H), -0.94 (s, br, 3 H, B--CH₃), -1.52 (s, br, I H, Zr--H--Zr).The chemical shifts and splitting patterns of ¹⁹ F NMR are same as thoseof Example 3 (L=C₅ H₃ Me₂). Anal. Calcd for C₆₅ H₄₂ BF₂₇ Zr₂ : C, 51.05;H, 2.77; N, 0.00. Found: C, 51.07; H. -2.63; N. 0.00.

Example 5 Preparation of L₂ ZrMe⁺ (MePBB)⁻

5(a) L=C₅ H₅.

In a J-Young NMR tube, a small amount of a mixture of L₂ ZrMe₂ and PBB(1:1.2 molar ratio) was dissolved in C₆ D₆). The NMR tube was then putin an NMR magnet and heated at 60° C. After 0.5 h, ¹ H NMR revealed theabove monomeric species formed. The same structures were obtained by thereaction of the product of Example 3 with excess of PBB at 60° C. for0.5 h. In a real polymerization test, these species were also generatedin situ by mixing L₂ ZrMe₂ and PBB at 60° C. for 0.5 h. ¹ H NMR (C₆ D₆,60° C.) for: δ 5.70 (s, 10 H, C₅ H₅), 0.14 (s, 3 H, Zr--CH₃), -0.85 (s,br, 3 H, B--CH₃). ¹⁹ F NMR is similar to that of the correspondingdinuclear species of Example 3 (L=C₅ H₅).

5(b) L=C₅ H₃ Me₂)

The same procedure of Example 5 (a) was used to prepare this species. Inthe polymerization test, the following was observed: ¹ H NMR (C₇ D₈, 60°C.) for 8: δ 5.68 (t, ³ J H-H=2.8 Hz, 4 H, C₅ H₃ Me₂), 5.36 (t, ³JH-H=3.1 Hz, 4 H, C₅ H₃ Me₂), 5.23 (t, ³ JH-H=2.8 Hz, 4 H, C₅ H₃Me₂).1.76 (s, 6 H, C₅ H₃ Me₂), 1.56 (s, 6 H, C₅ H₃ Me₂), 0.17 (s, 3 H,Zr--CH₃), -0.93 (s, br, 3 H, B--CH₃). ¹⁹ F NMR of this species issimilar to that of the corresponding dinuclear species of Example 3(L=C₅ Me₅). ¹³ C NMR (C₇ D₈, 60° C.): δ 117.74 (C₅ H₃ Me₂), 112.14 (C₅H₃ Me₂), 108.01 (C₅ H₃ Me₂), 42.11 (Zr--CH₃), 34.43 (B--CH₃), 12.63 (C₅H₂ Me₂), 12.45 (C₅ H₂ Me₂).

5(c) L=C₅ Me₅

The same procedure of Example 5 (a) was used to prepare this species. Inthe polymerization test, the following was observed: ¹ H NMR (C₆ D₆, 60°C.): 67 1.61 (s, 30 H, C₅ Me₅), 0.13 (s, 3 H, Zi--CH₃), -0.86 (s, br, 3H, B--CH₃). ¹⁹ F NMR is similar to that of the corresponding dinuclearspecies of Example 3, L=C₅ Me₅.

Example 6 Synthesis of LM(Me)₂ ⁺ (MePBB)⁻ L=C₅ Me₅

M=Ti

The catalyst product of FIG. 5 was generated in the NMR tube reaction bymixing C₅ Me₅ TiMe₃ and PBB at 1:1 molar ratio in C₆ D₆ for 2 h. ¹ H NMR(C₆ D₆, 23° C.): δ 9.03 (s, br, 2 H. CH₂), 1.69 (s, 6 H, C₅ Me₄), 1.65(s, 6 H, C₅ Me₄), 0.15 (s, 3 H, Ti--CH₃), -0.82 (s, br, 3 H, B--CH₃). ¹⁹F NMR is similar to that of Example 6.

Example 7 Synthesis of Me₂ Si(tBuN-)(C₅ Me₄)MMe⁺ (MePBB)⁻

7(a) M=Zr

Me₂ Si(tBuN-)(C5Me₄)MMe₂ (0.199 mmol) and PBB (0.199 mmol) were treatedin the same manner as in the preparation of Example 1 except for thedifferent reaction times (2 h). This procedure yields 73.1% (yellowsolid). Analytical and spectroscopic data are as follows. ¹ H NMR (C₇D₈, 23° C.): δ 1.73 (s, 3 H, C₅ Me₄), 1.69 (s, 3 H, C₅ Me₄), 1.63 (s, 3H, C₅ Me₄), 1.43 (s, 3 H, C₅ Me₄), 0.85 (s, 9 H, N-tBu), 0.28 (s, 3 H,SiMe₂), 0.21 (s, 3 H, SiMe₂), -0.48 (s, 3 H, Zr--CH₃), -0.95 (s, br, 3H, B--CH₃). ¹⁹ F NMR (C₇ D₈, 23° C.): δ -124.20 (s, br, 3 F), -139.14(d, ³ J_(F-F) =23.7 Hz, 3 F), -139.35 (d, ³ J_(F-F) =22.0 Hz, 3 F),-139.93 (d, ³ J_(F-F) =21.2 Hz, 3 F), -155.79 (t, ³ J_(F-F) =21.2 Hz, 3F), -159.67 (t, ³ J_(F-F) =22.3 Hz, 3 F), -163.28 (t, ³ J_(F-F) =21.7Hz, 3 F), -163.87 (t, ³ J_(F-F) =22.6 Hz, 3 F), -164.13 (t, ³ J_(F-F)=22.6 Hz, 3 F). ¹³ C NMR (C₇ D₈, 23° C.): δ 114.05 (C₅ Me₄), 113.94 (C₅Me₄), 112.58 (C₅ Me₄), 112.31 (C₅ Me₄), 112.02 (C₅ Me₄), 58.50(Zr--CH₃), 47.10 (N--CMe₃), 34.37 (N--CMe₃), 34.10 (B--CH₃), 15.89 (C₅Me₄), 13.46 (C₅ Me₄), 11.77 (C₅ Me₄), 10.99 (C₅ Me₄), 7.92 (SiMe₂), 5.65(SiMe₂). Anal. Calcd for C₅₃ H₃₃ BF₂₇ NSiZr: C, 47.97; H, 2.51; N, 1.06,Found: C, 47.79; H, 2.58; N, 0.86.

7(b) M=Ti

The same procedure as Example 3 was followed: Cp'TiMe₃ and PBB weremixed at a 1:1 molar ration in C₆ D₆ for 2 hours. 47.0% of an orangesolid was recovered. Analytical and spectroscopic data are: ¹ H NMR (C₆D₆, 23° C.): δ 9.03 (s, br, 2 H, CH₂), 1.69 (s 6 H, C₅ Me₄), 1.65 (s 6H, C₅ Me₄), 0.15 (s, 3 H, Ti--CH₃), -0.82 (s, br, 3 H,B--CH₃) ¹⁹ F NMRis similar to that of 10.

Example 8 Ethylene Polymerization

The reaction was conducted in a 250 mL flamed round bottom flaskattached to a high vacuum line. The flask was equipped with a largemagnetic stirring bar and a straight-bore high vacuum stopcock. Theexterior connecting tube of the stopcock (Ca. 10 mm in length) is sealedwith a new serum cap. The reaction vessel is then evacuated down forseveral hours, back filled with inert gas (Ar), the stopcock closed andthe reaction flask reevacuated. A measured amount of a nonpolar solventsuch as benzene or toluene is vacuum transferred into the flask. Gaseousethylene is admitted to the reaction flask through the purificationcolumn. The gas pressure is continuously maintained at 1 atm. Rapidstirring of the solution is initiated and after several minutes (toallow the saturation of the solvent with ethylene), the stopcock isopened and a small aliquot of catalyst solution (in the same solvent asused for the reaction) is injected by a gas-tight syringe just above therapidly stirring solution through a serum cap (the syringe needle hadbeen flattened so that the catalyst solution exits in a fine spray).Solid polyethylene is formed immediately. The reaction is quenched aftera certain amount of time by injecting methanol thiough the serum cap onthe stopcock. The solid polyethylene was collected by filtration, washedwith methanol and then dried under vacuum at 100° C. Copolymerizationmay occur with the addition of a second monomer such as anotherα-olefin.

Ethylene polymerizations were carried out at room temperature in 250-mLflamed, round-bottom flasks attached to a high-vacuum line. In a typicalexperiment, a solution of each of the catalysts of Example 3 in 2 mL oftoluene was quickly injected using a gas-tight syringe equipped with aspraying needle into respective rapidly stirred flasks containing 100 mLof toluene which was pre-saturated under 1 atm of rigorously purifiedethylene. In the case of the catalysts prepared in Example 4, thecatalyst solution was generated in situ by mixing L₂ ZrMe₂ and PBB in 2mL of toluene after aging for 0.5 h at 60° C., and then quickly injectedinto respective flasks under an ethylene atmosphere using a pre-warmedgas-tight syringe. The polymerization was quenched with acidic CH₃ OHafter a short time period (10-60 s) at which point voluminous quantitiesof polyethylene precipitated out. The respective polymeric products werecollected by filtration, washed with methanol and dried under highvacuum to a constant weight.

Example 9 Ring-Opening Polymerization of THF

A small amount of [(C₅ H₃ Me₂)₂ ZrMe₂ Zr Me₂ (C₅ H₃ Me₂)₂ ]⁺ (MePBB)⁻was loaded into a J-Young NMR tube and THF-d₈ was thenvacuum-transferred into the tube. The mixture was slowly warmed to roomtemperature and left for several hours. The solid polymer formed in thetube was shown to be polytetrahydrofuran by ¹ H analysis.

Example 10 Propylene Polymerization

This reaction is carried out in a 100 mL quartz Worden vessel equippedwith a magnetic stirring bar, a pressure gauge and a stainless steelo-ring assembly attached to a high vacuum line. In a typical experiment,the reaction vessel is flamed and then pumped under high vacuum forseveral hours, filled with inert gas and brought into a glove box. Ameasured amount of catalyst is added into the vessel. On the high vacuumline, a measured amount of the solvent and propylene are condensed at-78° C. The reaction apparatus is sealed off and warmed to the desiredtemperature. During the polymerization process, the reaction tube isimmersed in a large amount of tap water (20° C.-25° C.) or ice water (0°C.) to help dissipate the heat produced from the polymerization and keepthe temperature constant. The progress of the polymerization reactionsis monitored through observance of the pressure change. After thereaction is finished (pressure drops to zero psi), the resulting oilyliquid is removed from the vessel, washed with methanol and water anddried under vacuum at 90-100° C. for ten hours to result in a colorlessoil.

Table II sets forth the relevant data concerning propylenepolymerization utilizing the catalyst prepared according to theenumerated example.

                  TABLE II                                                        ______________________________________                                               Example:                                                               Metallocene                                                                            9                10                                                  Cation/Anion*                                                                          (Cp.sub.2)ZrMe).sub.2 Me.sup.+ /(MePBB).sup.-                                                  (Cp.sub.2 ZrMe.sup.+)/(MePBB).sup.-                 ______________________________________                                        catalyst (mM)                                                                          0.15             0.15                                                Reaction 40               40                                                  time(m)                                                                       Yield(g) 4.0              5.0                                                 ______________________________________                                         *Cp = C.sub.5 H.sub.5                                                    

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments and equivalents falling within the scope ofthe appended claims.

Various features of the invention are set forth in the following claims.

What is claimed is:
 1. A method of polymerizing an α-olefin orcopolymerizing a mixture of α-olefins comprising the steps of adding acatalyst (LL'MR)⁺ (RBR'R")⁻ to said α-olefin where

    ______________________________________                                        L,L'  =      C.sub.5 H.sub.n R.sub.5-n, indenyl, allyl benzyl, C.sub.5                     H.sub.n R.sub.4-n XNR                                            M     =      Th, Zr, Hf, Ti or U;                                             X     =      R.sub.2 '''Si, where R''' is an alkyl or aryl group (C                        ≦ 10)                                                     R, R'''                                                                             =      alkyl, benzyl, or aryl group (C ≦ 20), hydride,                        silyl                                                            B     =      Boron                                                            R'    =      flurinated biphenyl                                              R''   =      fluorinated phenyl, fluorinated biphenyl, or fluorinated                      polycyclic fused rings.                                          ______________________________________                                    


2. The method of claim 1 wherein said reaction is carried out at ambientconditions.
 3. The method of claim 1 wherein said reaction is initiatedat -78° C. and slowly warmed to ambient temperatures.
 4. The method ofclaim 1 wherein said reaction is carried out at a temperature from -78°C. to 200° C.
 5. The method of claim 1 wherein said monomer is ethylene.6. The method of claim 1 wherein said monomer is propylene.
 7. Themethod of claim 1 wherein said monomer is added to a second monomer toresult in a copolymerization reaction.
 8. A method of oligomerizing anα-olefin or a mixture of α-olefins comprising the steps of adding acatalyst (LL'MR)⁺ (RBR'R")⁻ to said α-olefin where

    ______________________________________                                        L,L'  =      C.sub.5 H.sub.n R.sub.5-n, indenyl, allyl benzyl, C.sub.5                     H.sub.n R.sub.4-n XNR                                            M     =      Th, Zr, Hf, Ti or U                                              X     =      R.sub.2 '''Si, where R''' is an alkyl or aryl group (C                        ≦ 10)                                                     R, R'''                                                                             =      alkyl, benzyl, or aryl group (C ≦ 20), hydride,                        silyl                                                            B     =      Boron                                                            R'    =      flurinated biphenyl                                              R''   =      fluorinated phenyl, fluorinated biphenyl, or fluorinated                      polycyclic fused rings                                           ______________________________________                                    


9. The method of claim 8 wherein said oligomerization comprisesprimarily a dimerization reaction.
 10. A method of polymerizingtetrahydrofuran comprising the steps of adding a catalyst (LL'MR)⁺(RBR'R")⁻ to said tetrahydrofuran where

    ______________________________________                                        L,L'  =      C.sub.5 H.sub.n R.sub.5-n, indenyl, allyl benzyl, C.sub.5                     H.sub.n R.sub.4-n XNR                                            M     =      Th, Zr, Hf, Ti or U;                                             X     =      R.sub.2 '''Si, where R''' is an alkyl or aryl group (C                        ≦ 10)                                                     R, R'''                                                                             =      alkyl, benzyl, or aryl group (C ≦ 20), hydride,                        silyl                                                            B     =      Boron                                                            R'    =      flurinated biphenyl                                              R''   =      fluorinated phenyl, fluorinated biphenyl, or fluorinated                      polycyclic fused rings.--                                        ______________________________________                                    